Hypertensive Crisis Flashcards
Definition of hypertension
SBP >/= 140mmHg and/or diastolic BP >/= 90mmHg
Hypertensive crisis refers to ___ and comprises of ___
Sudden, severe elevations in BP; Hypertensive emergency and hypertensive urgency
Definition of hypertensive emergency
Severe hypertension WITH acute end organ dysfunction in heart, brain, retina, kidneys or large arteries
- usually SBP >/= 180mmHg and/or DBP >/= 120mmHg
- acute rise in BP + target organ damage can be considered as htn emergency (esp in younger patients)
Definition of hypertensive urgency (uncontrolled hypertension)
Severe hypertension WITHOUT acute/ongoing end organ dysfunction
- usually SBP >/= 180mmHg and/or DBP >/= 120mmHg
*more common
Difference between htn emergency and htn urgency
htn emergency
- presents with acute end organ damage
- requires rapid lowering of bp
htn urgency
- presents without acute end organ damange
- requires gradual lowering of bp
Most important factor influencing prognosis of patients with htn urgency
Long term control of BP to ensure chronic bp control and prevent future episodes
What do the terms ‘accelerated hypertension’ or ‘malignant hypertension’ mean?
Severe hypertension associated with retinal changes, such as papilloedema, haemorrhages and cotton wool spots
Pathophysiology in HTN
BP is affected by changes in stroke volume (SVS), heart rate (HR), and systemic vascular resistance (SVR)
CO = HR x SV
BP = CO x SVR
Mean arterial pressure = 1/3(SBP-DBP) + DBP
In both chronic hypertension and hypertensive crisis, conditions affecting SVR, HR and SV will lead to changes in BP.
Instead of looking at absolute level of BP, what is more important? Why?
Rate of rise of BP
In patients with chronic hypertension, adaptive changes in the vasculature provide some protection and end organ dysfunction may only occur at a much higher BP (eg. SBP >/= 180); in contrast, a normotensive patient may suffer complications at a lower BP (eg. SBP >/= 140)
Presence of adaptive vascular changes in chronic hypertensive patients means that over-zealous correction of the BP in these patients may be hazardous leading to stroke or AMI
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Patient comes in to the polyclinic with SBP > 180mmHg, what are the next steps to take?
- Recheck BP automatically and manually with appropriate cuff size
- Check for home readings
- Check for white coat hypertension or in pain? - Look for acute, ongoing end organ damage
- Fundoscopy: papilloedema, haemorrhages
- Neurological examination: AMS, focal deficits
- CVS examination: left ventricular failure, new aortic regurgitation murmurs
Investigations to send off for suspected hypertensive emergency
POCTs:
- ECG
- Urine dipstick for haematuria, proteinuria
- UPT in females of child-bearing age with new HTN (TRO pre-eclampsia)
Bloods:
- FBC
- Renal panel
- LFT if patient is pregnant to identify HELLP syndrome (Haemolysis, Elevated Liver enzymes and Low Platelet count)
- Cardiac troponin
Radiology:
- CXR for left ventricular failure and widened mediastinum
- CT brain for AMS patients due to high risk of bleed
Management of hypertensive emergency
- Recheck BP automatically and manually with appropriate cuff size
- ABCs, set IV plug and closely monitor patient
- Send off investigations
- Monitor ECG, pulse oximetry, check vital signs every 5 to 10 minutes
- Invasive arterial BP monitoring is ideal if available
- Treatment should be focused on the specific conditions that resulted from the emergency
- Pharmaco for RAPID BP lowering:
- IV labetalol
- IV propanolol
- IV esmolol
- IV phentolamine
- IV GTN
- IV nitroprusside
- IV hydralazine
- IV nicardipine
- IV fenoldopam
- IV enalaprilat - Disposition: Admit ICU
Presentations of Hypertensive emergencies (THINK systems)
Neurologic
- Acute ischaemic stroke
- Hypertensive encephalopathy
- Intracerebral haemorrhage and subarachnoid haemorrhage
Cardiac
- Acute left ventricular failure (acute pulmonary oedema)
- AMI/ACS
Renal
- Acute renal failure
Vascular
- Aortic dissection
Pre-eclampsia
Sympathetic / Catecholamine Crisis
Management for Hypertensive Urgency
- Lower BP gradually over 24-48 hours to target DBP of 100-110mmHg
- Monitor BP closely and assess for any new onset symptoms suggestive of end-organ damage - ORAL medications should be used to control BP:
- PO Felodipine
- PO Amlodipine
- PO Extended release Nifedipine
- PO Captopril
- PO Labetalol
- PO Prazosin
- PO Clonidine - Disposition: Discharge if response is prompt and BP is acceptable after 4 hours of monitoring + TCU 48 hours later
